The present disclosure relates to image processor for reducing noise included in captured images.
Japanese Patent Publication No. H09-138849 describes an image processor in which axes are spatially arranged in a random manner from a target pixel in an image and pixels on the axes are subjected to noise smoothing. This technique can reduce uneven distribution, to a low-frequency range, of frequency components of noise included in a processed image.
Another image processing technique of performing noise smoothing in consideration of the difference in pixel value between a target pixel and its adjacent pixels in an image is described in C. Tomash and R. Maduchi, “Bilateral Filtering for Gray and Color Images,” Proceedings of the 1998 IEEE International Conference on Computer Vision, Bombay, India. This technique can reduce noise, while preserving a pattern in the image.